DEV Community: Deepak Sir

ColdFusion cfdocument PDF Generation at Scale: Queueing, Caching, and S3 Offloading

Deepak Sir — Wed, 03 Jun 2026 07:42:27 +0000

cfdocument works well for low-volume PDF generation, but at scale it becomes a bottleneck because PDF rendering is CPU-intensive and runs synchronously on a request thread. The three highest-leverage fixes are: (1) move generation off the request thread with a queue using cfthread or runAsync(), (2) cache finished PDFs so identical documents are never re-rendered, and (3) offload storage and delivery to Amazon S3 using ColdFusion's native s3:// file support. Together, these keep your web tier responsive under heavy PDF load.
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Tomcat 10.1 Optimization for ColdFusion 2025: Config Settings That Actually Matter

Deepak Sir — Tue, 02 Jun 2026 09:28:46 +0000

There’s a familiar pattern when a new ColdFusion version drops. Within weeks, dozens of blog posts appear listing forty JVM flags and twenty Tomcat connector attributes you “must” tune. Most of them are copied from each other. Some are flags that haven’t existed since Java 8. A few are actively harmful on modern JDKs. And the actual settings that move the needle in production rarely make the top of the list.
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ColdFusion Thread-Per-Request Model: When It Breaks and How to Work Around It

Deepak Sir — Mon, 01 Jun 2026 06:22:08 +0000

Most of the time, ColdFusion’s threading model is invisible. A request comes in, a thread picks it up, the page runs, the thread goes back to the pool, the next request gets served. It’s the standard servlet container pattern — predictable, well-understood, and quietly handling millions of CFML requests every day across thousands of production servers.
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Session Scope Memory Bloat in ColdFusion: Diagnosing and Eliminating the Hidden Culprit

Deepak Sir — Fri, 29 May 2026 05:34:14 +0000

The pattern is familiar enough that experienced ColdFusion teams stop being surprised by it. Server restarts at 7am. Fresh JVM, healthy heap. By mid-afternoon, response times creep up. By early evening, GC pauses are getting frequent and longer. By 11pm, somebody is restarting the server again. The dashboard says “memory leak.” The bug tracker has no recent code changes. The DBA swears the database is fine.
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ColdFusion Query Caching vs ORM vs qb: Which One Performs Better at Scale?

Deepak Sir — Thu, 28 May 2026 07:53:03 +0000

Ask three ColdFusion developers which data-access approach is fastest and you’ll get four opinions and a flame war. One swears by cachedWithin. One built the whole app on Hibernate-backed ORM and won't hear otherwise. The third installed qb last quarter and now writes everything as fluent chains. At low traffic, all three feel fine. The question only gets interesting under load — and that's exactly where the marketing answers fall apart.
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Why Your ColdFusion App Slows Under Load — and How FusionReactor Reveals the Cause

Deepak Sir — Wed, 27 May 2026 10:25:09 +0000

Your ColdFusion app runs fine in QA. Response times look healthy on a quiet Tuesday morning. Then traffic spikes — a marketing push, a quarterly report run, the first Monday after a release — and the same app starts taking 4 seconds to load a page that should take 200 milliseconds. Logs say “request completed.” Nothing crashed. Nothing errored. It just got slow.
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ColdFusion JVM Tuning: How Much RAM to Allocate and Which G1GC Flags Actually Work

Deepak Sir — Tue, 26 May 2026 08:42:01 +0000

ColdFusion’s jvm.config still ships with -XX:+UseParallelGC as the default garbage collector — not G1GC — even on ColdFusion 2025 running JDK 21 LTS. This is verified across multiple Adobe and community sources. If you don't explicitly change it, your CF server is using the throughput-optimized Parallel collector, not the low-pause G1 collector that most modern Java tuning guides assume. For heap sizing: per cfguide.io's CF 2025 documentation, allocate 50-70% of system RAM for the JVM heap, with 4-8GB as a starting point for production that you adjust based on actual usage. Set -Xms equal to -Xmx to avoid resize churn. For G1GC: switch is justified when heap is larger than ~6GB or pause-time minimization matters more than throughput (per Charlie Arehart's published guidance). The flags that actually work in JDK 21 are -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:+UseStringDeduplication plus thread tuning. Flags to remove if present: -XX:+AggressiveOpts (removed in JDK 12), -XX:+UseConcMarkSweepGC (removed in JDK 14), -XX:PermSize / -XX:MaxPermSize (replaced by Metaspace in Java 8), -XX:+UseCompressedOops (default in JDK 7+, no need to specify). For very large heaps in JDK 21: Generational ZGC (-XX:+UseZGC -XX:+ZGenerational) is now production-ready and may outperform G1GC on heaps over 32GB.

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ColdFusion Modernization Without a Full Rewrite: An API-First Strangler Strategy

Deepak Sir — Mon, 25 May 2026 10:48:24 +0000

The Legacy CFML Modernization Paradox
Most CFML modernization conversations start with the same paradox.

The application works. It generates revenue. Users log in every day and get their jobs done. The CFML code is functional, if not always elegant. Replacing it with a “modern” stack — React frontend, Node.js or Spring backend, microservices — is a 12 to 36 month rewrite project that pauses every other initiative, exposes the organization to twelve months of integration risk, and produces (in the typical case) a system that has all the same business logic but is now expressed in TypeScript.

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ColdFusion Database Connection Pool Exhausted

Deepak Sir — Fri, 22 May 2026 10:46:59 +0000

ColdFusion connection pool exhaustion occurs for eight primary documented reasons: the “Restrict connections to” setting in ColdFusion Administrator is lower than concurrent traffic demands; application code leaks connections by leaving queries, transactions, or ORM sessions unclosed; long-running queries without timeout attributes hold connections indefinitely; cfthread background processing spawns connections that never return to the pool; the database server's own max_connections limit sits below the ColdFusion pool size; stale or dead connections accumulate because "Validate Connection" is disabled; idle connection cleanup is misconfigured and ColdFusion only closes five connections per interval by design; and ColdFusion does not use the connection pool when issuing KILL QUERY commands — it creates a brand new connection that itself consumes pool capacity. The fix requires tuning datasource configuration, eliminating leaks at the code level, and aligning pool limits across every layer of the stack.

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How to Migrate ColdFusion to Lucee: Pitfalls, Wins, and Timeline Estimates

Deepak Sir — Thu, 21 May 2026 11:55:35 +0000

Lucee is an open-source CFML engine (LGPL-licensed, stewarded by the Lucee Association Switzerland), originally forked from Railo CFML Server 4.2, currently at Lucee 6. Its own documentation describes it as “highly compatible” with Adobe ColdFusion but not 100% drop-in — most CFML ports without changes, but a small set of verified differences will catch you if you don’t plan for them. The biggest pitfalls: arrays are passed by reference in Lucee, by value in Adobe CF; local scope behavior differs; JSON casing is different; CFX native tags don’t work; Verity is gone; and PDF/Chart/ORM features are extensions (not built-in). The biggest wins: zero licensing cost, smaller footprint, Docker-native deployment, per-application configuration, and an active open-source community. Realistic timelines: 4–8 weeks for small applications (under 50k lines), 3–6 months for mid-sized (50k-250k lines), 6–18 months for large enterprise codebases (500k+ lines) — assuming a Fixinator-driven compatibility scan upfront, not a “just install Lucee and see what breaks” approach.

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ColdFusion to AWS: Strangler-Pattern Migration Without Rewriting Everything

Deepak Sir — Wed, 20 May 2026 09:50:48 +0000

The Dilemma Every ColdFusion Shop Faces in 2026
A medium-sized enterprise is running a 250,000-line ColdFusion application on three on-prem servers. The application processes invoices, runs customer-facing portals, generates PDFs, sends emails, and integrates with five external partners via SOAP. It has been running for fifteen years. It works.
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ColdFusion Service Consuming Excessive RAM Over Time

Deepak Sir — Tue, 19 May 2026 06:29:46 +0000

The server starts fresh on Monday morning. ColdFusion uses 1.2 GB of RAM. The application responds in milliseconds. Users are happy. By Wednesday, RAM is at 2.8 GB. Response times have crept up. Garbage collection runs every 30 seconds now. By Friday, the server is at 4.5 GB of RAM and the CPU spikes to 100% on every GC cycle. Users complain about timeouts. Saturday’s monitoring alert fires at 2 AM. The server is dead. The on-call engineer restarts ColdFusion. The clock resets. The cycle begins again.
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